systemd: move basic systemd library to shared/nm-utils

For better or worse, we already pull in large parts of systemd sources.

I need a base64 decode implementation (because glib's g_base64_decode()
cannot reject invalid encodings). Instead of coming up with my own or
copy-paste if from somewhere, reuse systemd's unbase64mem().

But for that, make systemd's basic bits an independent static library
first because I will need it in libnm-core.

This doesn't really change anything except making "libnm-systemd-core.la"
an indpendent static library that could be used from "libnm-core". We
shall still be mindful about which internal code of systemd we use, and only
access functionality that is exposed via "systemd/nm-sd-utils-shared.h".

shared/systemd/src/basic/time-util.h

@@ -0,0 +1,179 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <time.h>
+
+typedef uint64_t usec_t;
+typedef uint64_t nsec_t;
+
+#define PRI_NSEC PRIu64
+#define PRI_USEC PRIu64
+#define NSEC_FMT "%" PRI_NSEC
+#define USEC_FMT "%" PRI_USEC
+
+#include "macro.h"
+
+typedef struct dual_timestamp {
+        usec_t realtime;
+        usec_t monotonic;
+} dual_timestamp;
+
+typedef struct triple_timestamp {
+        usec_t realtime;
+        usec_t monotonic;
+        usec_t boottime;
+} triple_timestamp;
+
+#define USEC_INFINITY ((usec_t) -1)
+#define NSEC_INFINITY ((nsec_t) -1)
+
+#define MSEC_PER_SEC  1000ULL
+#define USEC_PER_SEC  ((usec_t) 1000000ULL)
+#define USEC_PER_MSEC ((usec_t) 1000ULL)
+#define NSEC_PER_SEC  ((nsec_t) 1000000000ULL)
+#define NSEC_PER_MSEC ((nsec_t) 1000000ULL)
+#define NSEC_PER_USEC ((nsec_t) 1000ULL)
+
+#define USEC_PER_MINUTE ((usec_t) (60ULL*USEC_PER_SEC))
+#define NSEC_PER_MINUTE ((nsec_t) (60ULL*NSEC_PER_SEC))
+#define USEC_PER_HOUR ((usec_t) (60ULL*USEC_PER_MINUTE))
+#define NSEC_PER_HOUR ((nsec_t) (60ULL*NSEC_PER_MINUTE))
+#define USEC_PER_DAY ((usec_t) (24ULL*USEC_PER_HOUR))
+#define NSEC_PER_DAY ((nsec_t) (24ULL*NSEC_PER_HOUR))
+#define USEC_PER_WEEK ((usec_t) (7ULL*USEC_PER_DAY))
+#define NSEC_PER_WEEK ((nsec_t) (7ULL*NSEC_PER_DAY))
+#define USEC_PER_MONTH ((usec_t) (2629800ULL*USEC_PER_SEC))
+#define NSEC_PER_MONTH ((nsec_t) (2629800ULL*NSEC_PER_SEC))
+#define USEC_PER_YEAR ((usec_t) (31557600ULL*USEC_PER_SEC))
+#define NSEC_PER_YEAR ((nsec_t) (31557600ULL*NSEC_PER_SEC))
+
+/* We assume a maximum timezone length of 6. TZNAME_MAX is not defined on Linux, but glibc internally initializes this
+ * to 6. Let's rely on that. */
+#define FORMAT_TIMESTAMP_MAX (3+1+10+1+8+1+6+1+6+1)
+#define FORMAT_TIMESTAMP_WIDTH 28 /* when outputting, assume this width */
+#define FORMAT_TIMESTAMP_RELATIVE_MAX 256
+#define FORMAT_TIMESPAN_MAX 64
+
+#define TIME_T_MAX (time_t)((UINTMAX_C(1) << ((sizeof(time_t) << 3) - 1)) - 1)
+
+#define DUAL_TIMESTAMP_NULL ((struct dual_timestamp) {})
+#define TRIPLE_TIMESTAMP_NULL ((struct triple_timestamp) {})
+
+usec_t now(clockid_t clock);
+nsec_t now_nsec(clockid_t clock);
+
+dual_timestamp* dual_timestamp_get(dual_timestamp *ts);
+dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u);
+dual_timestamp* dual_timestamp_from_monotonic(dual_timestamp *ts, usec_t u);
+dual_timestamp* dual_timestamp_from_boottime_or_monotonic(dual_timestamp *ts, usec_t u);
+
+triple_timestamp* triple_timestamp_get(triple_timestamp *ts);
+triple_timestamp* triple_timestamp_from_realtime(triple_timestamp *ts, usec_t u);
+
+#define DUAL_TIMESTAMP_HAS_CLOCK(clock)                               \
+        IN_SET(clock, CLOCK_REALTIME, CLOCK_REALTIME_ALARM, CLOCK_MONOTONIC)
+
+#define TRIPLE_TIMESTAMP_HAS_CLOCK(clock)                               \
+        IN_SET(clock, CLOCK_REALTIME, CLOCK_REALTIME_ALARM, CLOCK_MONOTONIC, CLOCK_BOOTTIME, CLOCK_BOOTTIME_ALARM)
+
+static inline bool dual_timestamp_is_set(const dual_timestamp *ts) {
+        return ((ts->realtime > 0 && ts->realtime != USEC_INFINITY) ||
+                (ts->monotonic > 0 && ts->monotonic != USEC_INFINITY));
+}
+
+static inline bool triple_timestamp_is_set(const triple_timestamp *ts) {
+        return ((ts->realtime > 0 && ts->realtime != USEC_INFINITY) ||
+                (ts->monotonic > 0 && ts->monotonic != USEC_INFINITY) ||
+                (ts->boottime > 0 && ts->boottime != USEC_INFINITY));
+}
+
+usec_t triple_timestamp_by_clock(triple_timestamp *ts, clockid_t clock);
+
+usec_t timespec_load(const struct timespec *ts) _pure_;
+nsec_t timespec_load_nsec(const struct timespec *ts) _pure_;
+struct timespec *timespec_store(struct timespec *ts, usec_t u);
+
+usec_t timeval_load(const struct timeval *tv) _pure_;
+struct timeval *timeval_store(struct timeval *tv, usec_t u);
+
+char *format_timestamp(char *buf, size_t l, usec_t t);
+char *format_timestamp_utc(char *buf, size_t l, usec_t t);
+char *format_timestamp_us(char *buf, size_t l, usec_t t);
+char *format_timestamp_us_utc(char *buf, size_t l, usec_t t);
+char *format_timestamp_relative(char *buf, size_t l, usec_t t);
+char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy);
+
+int parse_timestamp(const char *t, usec_t *usec);
+
+int parse_sec(const char *t, usec_t *usec);
+int parse_sec_fix_0(const char *t, usec_t *usec);
+int parse_time(const char *t, usec_t *usec, usec_t default_unit);
+int parse_nsec(const char *t, nsec_t *nsec);
+
+bool ntp_synced(void);
+
+int get_timezones(char ***l);
+bool timezone_is_valid(const char *name, int log_level);
+
+bool clock_boottime_supported(void);
+bool clock_supported(clockid_t clock);
+clockid_t clock_boottime_or_monotonic(void);
+
+usec_t usec_shift_clock(usec_t, clockid_t from, clockid_t to);
+
+int get_timezone(char **timezone);
+
+time_t mktime_or_timegm(struct tm *tm, bool utc);
+struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc);
+
+unsigned long usec_to_jiffies(usec_t usec);
+
+bool in_utc_timezone(void);
+
+static inline usec_t usec_add(usec_t a, usec_t b) {
+        usec_t c;
+
+        /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output, and doesn't
+         * overflow. */
+
+        c = a + b;
+        if (c < a || c < b) /* overflow check */
+                return USEC_INFINITY;
+
+        return c;
+}
+
+static inline usec_t usec_sub_unsigned(usec_t timestamp, usec_t delta) {
+
+        if (timestamp == USEC_INFINITY) /* Make sure infinity doesn't degrade */
+                return USEC_INFINITY;
+        if (timestamp < delta)
+                return 0;
+
+        return timestamp - delta;
+}
+
+static inline usec_t usec_sub_signed(usec_t timestamp, int64_t delta) {
+        if (delta < 0)
+                return usec_add(timestamp, (usec_t) (-delta));
+        else
+                return usec_sub_unsigned(timestamp, (usec_t) delta);
+}
+
+#if SIZEOF_TIME_T == 8
+/* The last second we can format is 31. Dec 9999, 1s before midnight, because otherwise we'd enter 5 digit year
+ * territory. However, since we want to stay away from this in all timezones we take one day off. */
+#define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 253402214399000000)
+#elif SIZEOF_TIME_T == 4
+/* With a 32bit time_t we can't go beyond 2038... */
+#define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 2147483647000000)
+#else
+#error "Yuck, time_t is neither 4 nor 8 bytes wide?"
+#endif
+
+int time_change_fd(void);